Jerusalem (CNN) -- Palestinian negotiators agreed to give up large swaths of East Jerusalem to Israel during negotiations dating back to 2008, the Al-Jazeera network said Sunday, suggesting Palestinians have been willing to offer much larger concessions in private than what was previously acknowledged in public.

The report is based on a trove of nearly 1,700 internal documents the network said it had obtained. Al-Jazeera did not disclose the source of the material, nor did it say how the documents came into its possession. It said it will be releasing what it has between Sunday and Wednesday of this week.

The papers, some of which were posted on the network's website, shed new light on the details of the Israeli-Palestinian conflict from 1999 through last year. They could not be immediately verified by CNN.

The documents outline meetings between Israeli, Palestinian and U.S. officials in which Palestinian negotiators offered in 2008 to relinquish claims on nearly all of the settlements built in East Jerusalem.

The offer was flatly rejected by the Israeli side, according to the posted documents.

Israel seized the eastern half of the city following war with its Arab neighbors in 1967 and considers Jerusalem its sovereign capital. This is a claim rejected by the international community that considers Israeli building in East Jerusalem to be illegal. Palestinians want the eastern part of the city as the capital for their future state.

The leaked documents could prove to be politically damaging for Palestinian Authority President Mahmoud Abbas. Officials from the Ramallah-based government have consistently condemned growing Israeli settlements in East Jerusalem and disclosures that Palestinians officials were willing to make offers that would allow Israeli construction to continue are likely to be seized on by their critics.

In one leaked document from 2010, chief Palestinian negotiator Saeb Erekat is quoted as telling a U.S. state department official, "Israelis want the two-state solution but they don't trust. They want it more than you think, sometimes more than the Palestinians. What is in that paper (that) gives them the biggest (Jerusalem) in Jewish history ... what more can I give?"

In addition to details about concessions made on the issue of East Jerusalem, Al-Jazeera reported that Palestinian officials also offered compromise positions on sensitive issues like the right of return of Palestinian refugees and control of the Temple Mount, which houses the Al-Aqsa mosque, one of the most important sites in Islam.

Wafa, the Palestinian Authority's news agency, quoted President Abbas telling newspaper editors in Cairo Sunday that he did not know where Al-Jazeera got its information and that there was nothing new to report.

U.S. State Department spokesman P.J. Crowley said Sunday night the United States is looking into the purported leak to Al-Jazeera.

"The U.S. government is reviewing the alleged Palestinian documents released by Al-Jazeera. We cannot vouch for their veracity," he tweeted.